Studies of chemical metabolism and disposition are designed to provide both applied knowledge in support of chronic toxicity tests conducted by the National Toxicology Program and basic knowledge of those chemical structure and property relationships which determine toxicity. Studies of benzyl acetate indicate that this compound is readily absorbed from the gastrointestinal tract, rapidly metabolized and excreted in urine primarily in the form of hippuric acid. Investigation of parameters of dermal absorption indicate that the effective dose of a chemical which can be applied dermally is limited by the physical properties of that chemical and the vehicle in which it is applied. Studies of the gastric toxicity of a series of acrylate esters indicate that these compounds are strong irritants to the forestomach of the rat, and rats adapt to the irritating effects of these chemicals with chronic exposure.